The present invention relates to a slide member with an overlay layer provided on a slide alloy layer, and more particular, to a slide member comprising an overlay layer formed from Bi or Bi alloy.
In a plain bearing (slide member) used for a main shaft of a crankshaft, a large end of a connecting rod, and the like for internal combustion engines, a constitution is general, in which a Cu base or Al base bearing alloy (slide alloy) is lined on an inner peripheral surface of steel back metal and plating is used to cover a surface of the bearing alloy with an overlay layer through an intermediate layer or not.
As the overlay layer, Pb alloy has been mainly used heretofore and Sn alloy has been partly used. Since Pb is an environmental contamination substance, however, there is a tendency of avoiding its use, and JP-A-2001-20955 has proposed Bi or Bi alloy as its substitute material.
While Bi is a low melting point metal like Pb, it is harder than Pb and inferior thereto in lipophilic property, so that it is low in anti-seizure. An improvement in anti-seizure is earnestly requested in using Bi or Bi alloy for an overlay layer.
The invention has been thought of in view of the above situation, and has its object to provide a slide member which is excellent in anti-seizure.